chap, xiii.] DIGITS : HORSE. 363 



Arloing as a representative of the metacarpal I, the carpal portion 

 of the bone being the trapezium. 



The outer metacarpal (IV) was perhaps slightly larger than 

 usual. 



The inner metacarpal (II) was greatly enlarged at its central 

 end, articulating with the tw r o bones t 1 and t' 2 , and partly with the 

 magnum. In its central part this metacarpal was fused with the 

 large metacarpal (III) and above is united to it by ligamentous 

 fibres. Below r it again separates from the large metacarpal and 

 is enlarged, bearing an additional digit of three phalanges, the 

 lowest bearing a hoof. [This hoof is not curved towards the large 

 hoof as in many specimens described, but is convex on both sides, 

 resembling the hoof of an ass.] The large central metacarpal was 

 flattened on the side adjacent to the enlarged metacarpal II. The 

 muscles, nerves and vessels are fully described (q. v.). Arloing. 

 M. S., Ann. Sci. Nat, ZooL, Ser. V. T. vm. pp. 61 — 67, PL 



534. Foal having two toes on each fore foot. The father and mother of 

 this foal w r ere both of the "variete chevaline comtoise." The foal in 

 question was the only one which this mare dropped and she died two 

 months afterwards. The foal w T as in nowise abnormal excepting for the 

 peculiarity of the fore feet. The carpus was normal and the external 

 metacarpal was rudimentary as usual and ends in a small knob. The 

 internal metacarpal is thicker than the external one and bears a digit 

 of three phalanges, the terminal phalanx bearing a small hoof. This 

 hoof is curved outwards towards the normal hoof. The ligaments and 

 tendons of the foot did not suffice to keep it stiff, and as the animal 

 walked, it not only touched the ground with the hoof but also with 

 the posterior surface of the phalanges. This led to inflammation of 

 the foot, in consequence of which the foal was killed. CORNEVIN, 

 Nouveaux cas de didactylie chez le chevcd, Lyons (1882?). [Xote that 

 this case differs from the last in the fact that the carpus was normal.] 



A similar case in the right forefoot is given by Kitt. Dent. Ztsch. 

 f. Thiermed., 1886, xn. Jahresb., 1884 — 5, p. 57, Jig. 



Hind foot. 



Among the many accounts of polydactyle horses I know none 

 which gives an anatomical description of a case of a fully developed 

 digit II in the hind foot. The following case, indeed, is the only one 

 known to me in which an}^ facts respecting the condition of the 

 tarsus of a polydactyle horse have been ascertained. In it, as will be 

 seen, the digit II was not fully developed. 



535. Horse having the metatarsal II enlarged and bearing a rudimentary 

 ' digit (Fig. 107 B and C). In the left hind foot the arrangement was as 



shewui in Figs. B and C. The metatarsal II was enlarged an. 1 articulated 

 with "two united cuneiform bones" [presumably one bone with indica- 

 tions of duplicity]. Internal to this digit was a " first cuneiform bone," 

 but the digit I was not developed. The metatarsal II bore peripherally 

 a rudiment of a digit as shewn in the figure. The right hind foot was 

 similar to the left but it is stated that the "three small cuneiform 



